Late-Holocene palaeoecology of a polygonal peatland on the south shore of Hudson Strait, northern Québec, Canada

Abstract

In order to document climate fluctuations during the late Holocene in Nunavik (in the Québec Arctic), a 182 cm peat core extracted from a polygonal peatland in the Salluit region was subjected to macrofossil and pollen analysis. Peat accumulation began around 4500 cal. BP in the peatland and 2340 cal. BP in the core site following the formation of frost cracks and ice wedges. Four distinct Holocene climatic changes were identified. Between 1910 and 1100 cal. BP, the climate was clement (similar to today’s climate), which favoured the growth of several species of Sphagnum (from poorly minerotrophic to ombrotrophic conditions). Colder and drier conditions starting around 1100 cal. BP are evidenced by the disappearance of Sphagnum and aeolian sedimentation. A short return to more clement conditions occurred around 870 cal. BP and lasted until 670 cal. BP. Subsequently, the climate once again became colder and drier, which induced significant aeolian activity. Late-Holocene local vegetation changes recorded in the peat core were probably induced by permafrost degradation and aggradation, associated with regional warming and a subsequent cooling trend.